A small leather attachment to the guard of a Medieval sword, usually shaped in a half-circle projecting out onto the ricasso.
First appearing ca. 1250 C.E., they were added so that the sword would have a tighter grip on the scabbard when sheathed and to create a nearly water-tight seal to prevent corrosion. When outfitted with a chappe, the sword was termed garnished.
Medieval Swordsmanship, by John Clements
European Weapons and Armor, by R.E. Oakeshott